A strategy for the formation of amide bonds with one side protection of diamine was reported. A method was found to obtain a large number of mono⁃side protective diamines. When the reaction temperature was 0 ℃, adding the protective group to diamine solution slowly did not need catalyst to synthesize tert⁃butyl N⁃(6⁃aminohexyl)carbamate. The reaction had strong selectivity and good universality. The reaction had strong selectivity and good universality. This process can selectively and efficiently obtain the single amino protection product. The excessive diamine can be recycled and utilized, which improves the utilization rate of raw materials. It is a green and environment⁃friendly reaction.